![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
I have heard/seen (once heard, once seen) media writers/readers use the form "big of a" today -- once on the CBC's Metro Morning (Matt Galloway) and once in a Globe and Mail article.
When I was growing up this formation was not possible. Now I seem to run into it in supposedly non-slangy contexts all over the place. It grates really seriously.
The CBC also had someone saying "like you and I". At least that is a venerable form, even if it elicits automatic talking back to the radio.
I'm not, as such, a prescriptivist, but the "big of a" usage seems to me to be disconnected from anything else I know in English grammar. It's like saying "how white of a piece of paper is it?"